The launch statement of the seven former Labour MPs who originally made up the Independent Group contained only one reference to leaving the EU.  It was aimed at Jeremy Corbyn.  His party, it said, “has failed to take a lead in addressing the challenge of Brexit and to provide a strong and coherent alternative to the Conservatives’ approach”.

By contrast, that of the three Tory MPs who left the Party recently put leaving the EU centre-stage: “Brexit has re-defined the Conservative Party – undoing all the efforts to modernise it,” it said.  The Independent Group will morph into a fully-fledged political party sooner or later.  And the difference between the two statements offers a clue about how it may turn out.

In the event of a revised deal with the EU passing Parliament, either before March 29 or afterwards, the Brexit talks will move on to their next stage.  At this point, the Party will return to a policy choice that has never really gone away: high alignment with the EU, roughly Norway-style, or lower alignment, in the general shape of Canada.

It is possible that there will be a clear shift to the latter, and that such a move, in turn, might see more Conservative MPs transfer to the Independent Group.  If there is no deal at all – the odds of which are lengthening, though the outcome is still possible – the aftermath might see the same effect.

But the more one ponders the Independent Group’s future, the more one comes to see that it presents a bigger problem for Labour.  Fundamentally, the Conservatives’ present problems are about EU policy.  Elsewhere, most Tory MPs and members are willing to muddle along with a Government that is, as this site has previously put it, mired in the mixed middle.

At heart, Labour’s problems stretch far wider.  They are about not only Corbyn himself but a wider shift in the party itself.  It may be that in the event of an election loss the party’s hard left members leave and a mass of New Labour-type voters sign up.  The party has certainly lost Remain-leaning members over its leader’s pro-Brexit instincts.

However, Momentum seems to be alive and kicking none the less, and the consensus view of many Labour MPs seems to be that there has been a fundamental change in the party’s membership and outlook, reflecting the wider post-crash problems of social democratic and democratic parties throughout the rest of Europe.

That being so, the Parliamentary Party is deeply divided not over one issue, but many: globalisation, anti-semitism, foreign policy, business, intervention abroad, defence.  All parties are coalitions, but there is a culture gap between its membership, concentrated in London, and voters in the mass of Labour-held seats outside the greater South-East.

These are early days, but many voters in the Labour column seem to feel the same way.  A new POLITICO-Hanbury poll this morning shows that a quarter of voters would consider voting for a party based on the Independent Group.  It also finds that 32 percent of Labour supporters say that they might, but only 19 per cent of Conservative ones.

Similar survey results elsewhere help to explain Corybn’s unwilling shift towards a second EU referendum.  (Younger voters and Londoners are among those most likely to back the Independent Group, according to the poll.)  Some of those who remember the 1980s will see a parallel.

There is dispute over whether the emergence of the SDP helped or harmed the Conservatives.  One view is that, if it had never been brought into being, Margaret Thatcher’s vote would have been ever bigger.  But there is more to politics than psephology, and a breakaway from Michael Foot’s Labour by high-profile former Ministers plainly did his party no good at all.

Today, the Independent Group has announced that Chuka Umunna is to be its Chief Spokesman (now, there’s a surprise).  Its allocation of other MPs to different portfolios will mark the start of problems, as they struggle to explain different approaches historically, and perhaps now, to Universal Credit, free schools, the benefits freeze, “austerity” and so on.

It could be that the eventual new party will vanish not with a bang, but a whimper.  Its biggest problem looks to be the interplay between a relatively even spread of the vote and first past the post. (The curse of the Liberal Democrats: talking of which, how will the new party deal with them, and vice-versa?)

But Labour’s shift left seems sufficiently well-established to offer it an opportunity.  And a bigger one to the Conservatives – as Corbynistas everywhere aren’t shy of pointing out.  There is a solid rationale for most Tories taking the departure of their three former colleagues calmly and courteously.